This invention relates generally to apparatus for stringing a plurality of high voltage conductors simultaneously and more particularly to a transfer mechanism for transferring a lead line for such conductors from the exterior of a bundle block to the interior of the block. In greater particularity, the invention may be described as a dual gate arrangement for maintaining the alignment of an open-sided block and closing the block after receiving the line.
The prior art helicopter stringing blocks have employed a number of devices to facilitate the transfer of the lead line to the interior of the frame. These devices include open-sided block as well as closed-head bundle block transfer means. By way of example, U.S. Pat. No. 3,479,014 shows a helicopter stringing block of the open-sided variety as does U.S. Pat. No. 3,837,623 and 3,868,089. These mechanisms however do not provide bi-lateral support for the conductors when the bundle block is fully loaded. Further, some open-sided blocks exhibit torsional distortion about a vertical axis which results in a misalignment of the frame members. To achieve such support and alignment U.S. Pats. Nos. 3,905,581 and 4,018,422 use rotating disc type gates. While such devices are suitable for their intended purpose, they are complicated in structure, difficult to operate and somewhat lacking in reliability under certain adverse weather conditions such as icing.